<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        var Fahrenheit = prompt('华氏摄氏度')
        var Centigrade = (5 / 9 * (Fahrenheit - 32)).toFixed(3)
        alert('摄氏度' + Centigrade)
    </script>
</body>

</html>